M30218 Datasheet, PDF (67/179 Pages) Mitsubishi Electric Semiconductor – M30218 Group

FLD controller
Mitsubishi microcomputers
M30218 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
The FLD blanking interrupt is generated when the FLD data pointer (address 035816) reaches “FF16”. The FLD automatic
display output is turned off for a duration of 1 x Tdisp, 2 x Tdisp, or 3 x Tdisp depending on post-interrupt settings. During
this time, key scanning that makes use of FLD segments can be achieved.
When a key-scan is performed with the segment during key-scan blanking period Tscan, take the following sequence:
1. Write “0” to bit 0 of the FLDC mode register (address 035016).
2. Set the port corresponding to the segment for key-scan to the output port.
3. Perform the key-scan.
4. After the key-scan is performed, write “1” to bit 0 of FLDC mode register (address 035016).
•Note:
When performing a key-scan according to the above steps 1 to 4, take the following points into consideration.
1. Do not set “0” in bit 1 of the FLDC mode register (address 035016).
2. Do not set “1” in the ports corresponding to digits.
FLD digit output
Repeat synchronous
Tdisp
Tn Tn-1 Tn-2
T4 T3 T2 T1
Tscan
Tn Tn-1 Tn-2
Segment setting by software
FLD blanking interrupt generated at the
falling of edge of the last digit
Figure KA-12B. Timing using FLD blanking interrupt
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